C

Green Card is a foreign function interface preprocessor for Haskell, simplifying the task of interfacing Haskell programs to external libraries (which are normally exposed via C interfaces). Green Card is currently able to generate code compatible with Hugs and nhc. Green Card is compatible with the Glasgow Haskell Compiler (GHC), versions prior to 6.2.

Green Card is not compatible with GHC versions 6.2 and later because Green Card uses a deprecated form of Foreign Function Interface (FFI) binding, _casm_: such old-style bindings were removed in GHC version 6.2. See ANNOUNCE: GHC version 6.2.

HaskellDirect is an Interface Definition Language (IDL) compiler for Haskell, which helps interfacing Haskell code to libraries or components written in other languages (C). An IDL specification specifies the type signatures and types expected by a set of external functions. One important use of this language neutral specification of interfaces is to specify COM (Microsoft's Component Object Model) interfaces, and HaskellDirect offers special support for both using COM objects from Haskell and creating Haskell COM objects. HaskellDirect groks both the OSF DCE dialect of IDL (including the various extensions introduced by the Microsoft IDL compiler) and the OMG IIOP/CORBA dialect.

A Haskell <=> Java interoperation bridge. Interoperation between Haskell and Java is provided by Lambada via the Java Native Interface (JNI), giving you a set of Haskell abstractions that lets you both call out to Java from Haskell *and* wrap up Haskell code behind a Java-callable veneer.

Python

MissingPy is really two libraries in one. At its lowest level, MissingPy is a library designed to make it easy to call into Python from Haskell. It provides full support for interpreting arbitrary Python code, interfacing with a good part of the Python/C API, and handling Python objects. It also provides tools for converting between Python objects and their Haskell equivalents. Memory management is handled for you, and Python exceptions get mapped to Haskell Dynamic exceptions. At a higher level, MissingPy contains Haskell interfaces to some Python modules.